What did you do to your Patrol today!

[Hodge]

If I bought itech 120's & their internal BMS lasted 4 years & I replaced them each four years at the same cost they would cost me around $4800 for 12 years or $400 per year - essentially 4 times the cost to do the same thing.

Again, where is this 4 year apparent life-span of the BMS coming from? I don't think the 120X has even been on the market for 4 years to my knowledge? What kills them? Usage? Heat? Corrugations? Lack of use? Wrongly charged?
Not questioning you, just wondering from a "concerned owner of one of them batteries , point of view" .

Personally, I believe, the way these lithium's are heading, say in 4 years time the prices will be a lot different... And the other chemistries used in vehicles will be close to being dinosaurs. When I bought my Optima the other week, having a quick chat with the bloke in the battery shop about Patrols, 12V and batteries, he mentioned things are swaying that way really quick... Good or bad? Time will tell.
Look back 4 years from now. Seeing a lithium in a 4x4 was a unicorn, met with a lot of "WoW' and "Whoasss". Look at the market now. Every company is flogging them out now. And one would like to think that they're getting better and improving .

But like you said, whatever works for each individuals purpose.
I sat on the "lithium vs. AGM" fence for ages. What made me pull the trigger was seeing my mates 2 x 120 itechs perform over a week of camping.
Albeit pricey, it was one of the best 12V decisions I ever personally made in so many aspects. Continuously watching the battery volts when camping over weekend or longer are a thing of the past now.